Signed-off-by: Stefan Reinauer <stepan@coresystems.de>

Acked-by: Jordan Crouse <jordan.crouse@amd.com>


git-svn-id: svn://svn.coreboot.org/coreboot/trunk@2736 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1

util/lxbios/cmos_ops.c

@@ -0,0 +1,221 @@
+/*****************************************************************************\
+ * cmos_ops.c
+ * $Id: cmos_ops.c,v 1.3 2006/01/24 00:25:40 dsp_llnl Exp $
+ *****************************************************************************
+ *  Copyright (C) 2002-2005 The Regents of the University of California.
+ *  Produced at the Lawrence Livermore National Laboratory.
+ *  Written by David S. Peterson <dsp@llnl.gov> <dave_peterson@pobox.com>.
+ *  UCRL-CODE-2003-012
+ *  All rights reserved.
+ *
+ *  This file is part of lxbios, a utility for reading/writing LinuxBIOS
+ *  parameters and displaying information from the LinuxBIOS table.
+ *  For details, see <http://www.llnl.gov/linux/lxbios/>.
+ *
+ *  Please also read the file DISCLAIMER which is included in this software
+ *  distribution.
+ *
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License (as published by the
+ *  Free Software Foundation) version 2, dated June 1991.
+ *
+ *  This program is distributed in the hope that it will be useful, but
+ *  WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the terms and
+ *  conditions of the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+\*****************************************************************************/
+
+#include "common.h"
+#include "cmos_ops.h"
+#include "cmos_lowlevel.h"
+
+static int prepare_cmos_op_common (const cmos_entry_t *e);
+
+/****************************************************************************
+ * prepare_cmos_op_common
+ *
+ * Perform a few checks common to both reads and writes.
+ ****************************************************************************/
+static int prepare_cmos_op_common (const cmos_entry_t *e)
+ { int result;
+
+   if (e->config == CMOS_ENTRY_RESERVED)
+      /* Access to reserved parameters is not permitted. */
+      return CMOS_OP_RESERVED;
+
+   if ((result = verify_cmos_op(e->bit, e->length)) != OK)
+      return result;
+
+   assert(e->length > 0);
+   return OK;
+ }
+
+/****************************************************************************
+ * prepare_cmos_read
+ *
+ * The caller wishes to read a CMOS parameter represented by 'e'.  Perform
+ * sanity checking on 'e'.  If a problem was found with e, return an error
+ * code.  Else return OK.
+ ****************************************************************************/
+int prepare_cmos_read (const cmos_entry_t *e)
+ { int result;
+
+   if ((result = prepare_cmos_op_common(e)) != OK)
+      return result;
+
+   switch (e->config)
+    { case CMOS_ENTRY_ENUM:
+      case CMOS_ENTRY_HEX:
+         break;
+
+      default:
+         BUG();
+    }
+
+   return OK;
+ }
+
+/****************************************************************************
+ * prepare_cmos_write
+ *
+ * The caller wishes to set a CMOS parameter represented by 'e' to a value
+ * whose string representation is stored in 'value_str'.  Perform sanity
+ * checking on 'value_str'.  On error, return an error code.  Else store the
+ * numeric equivalent of 'value_str' in '*value' and return OK.
+ ****************************************************************************/
+int prepare_cmos_write (const cmos_entry_t *e, const char value_str[],
+                        unsigned long long *value)
+ { const cmos_enum_t *q;
+   unsigned long long out;
+   const char *p;
+   int negative, result, found_one;
+
+   if ((result = prepare_cmos_op_common(e)) != OK)
+      return result;
+
+   switch (e->config)
+    { case CMOS_ENTRY_ENUM:
+         /* Make sure the user's input corresponds to a valid option. */
+         for (q = first_cmos_enum_id(e->config_id), found_one = 0;
+              q != NULL;
+              q = next_cmos_enum_id(q))
+          { found_one = 1;
+
+            if (!strncmp(q->text, value_str, CMOS_MAX_TEXT_LENGTH))
+               break;
+          }
+
+         if (!found_one)
+            return CMOS_OP_NO_MATCHING_ENUM;
+
+         if (q == NULL)
+            return CMOS_OP_BAD_ENUM_VALUE;
+
+         out = q->value;
+         break;
+
+      case CMOS_ENTRY_HEX:
+         /* See if the first character of 'value_str' (excluding any initial
+          * whitespace) is a minus sign.
+          */
+         for (p = value_str; isspace(*p); p++);
+         negative = (*p == '-');
+
+         out = strtoull(value_str, (char **) &p, 0);
+
+         if (*p)
+            return CMOS_OP_INVALID_INT;
+
+         /* If we get this far, the user specified a valid integer.  However
+          * we do not currently support the use of negative numbers as CMOS
+          * parameter values.
+          */
+         if (negative)
+            return CMOS_OP_NEGATIVE_INT;
+
+         break;
+
+      default:
+         BUG();
+    }
+
+   if ((e->length < (8 * sizeof(*value))) &&
+       (out >= (1ull << e->length)))
+      return CMOS_OP_VALUE_TOO_WIDE;
+
+   *value = out;
+   return OK;
+ }
+
+/****************************************************************************
+ * cmos_checksum_read
+ *
+ * Read the checksum for the LinuxBIOS parameters stored in CMOS and return
+ * this value.
+ ****************************************************************************/
+uint16_t cmos_checksum_read (void)
+ { uint16_t lo, hi;
+
+   /* The checksum is stored in a big-endian format. */
+   hi = cmos_read_byte(cmos_checksum_index);
+   lo = cmos_read_byte(cmos_checksum_index + 1);
+   return (hi << 8) + lo;
+ }
+
+/****************************************************************************
+ * cmos_checksum_write
+ *
+ * Set the checksum for the LinuxBIOS parameters stored in CMOS to
+ * 'checksum'.
+ ****************************************************************************/
+void cmos_checksum_write (uint16_t checksum)
+ { unsigned char lo, hi;
+
+   /* The checksum is stored in a big-endian format. */
+   hi = (unsigned char) (checksum >> 8);
+   lo = (unsigned char) (checksum & 0x00ff);
+   cmos_write_byte(cmos_checksum_index, hi);
+   cmos_write_byte(cmos_checksum_index + 1, lo);
+ }
+
+/****************************************************************************
+ * cmos_checksum_compute
+ *
+ * Compute a checksum for the LinuxBIOS parameter values currently stored in
+ * CMOS and return this checksum.
+ ****************************************************************************/
+uint16_t cmos_checksum_compute (void)
+ { unsigned i, sum;
+
+   sum = 0;
+
+   for (i = cmos_checksum_start; i <= cmos_checksum_end; i++)
+      sum += cmos_read_byte(i);
+
+   return ~((uint16_t) (sum & 0xffff));
+ }
+
+/****************************************************************************
+ * cmos_checksum_verify
+ *
+ * Verify that the LinuxBIOS CMOS checksum is valid.  If checksum is not
+ * valid then print warning message and exit.
+ ****************************************************************************/
+void cmos_checksum_verify (void)
+ { uint16_t computed, actual;
+
+   set_iopl(3);
+   computed = cmos_checksum_compute();
+   actual = cmos_checksum_read();
+   set_iopl(0);
+
+   if (computed != actual)
+    { fprintf(stderr, "%s: Warning: LinuxBIOS CMOS checksum is bad.\n",
+              prog_name);
+      exit(1);
+    }
+ }